Method of adhesion and composition therefor

Abstract

A method of adhesion which comprises applying a two-step reactive type tacky adhesive agent comprising (1) a non-photopolymerizable epoxy resin or isocyanate compound, (2) a curing agent therefor and (3) a compound having at least one photopolymerizable vinyl group in one molecule onto a substrate, irradiating the whole applied surface with light to develop the tackiness, and sticking the substrate together to a material to be bonded, while the tackiness is retained, followed by curing. The method provides excellent green bonding strength and can permit the satisfactory adhesion without clamping, and can be particularly suitably utilized in the adhesion of materials to be bonded which have a curved surface difficult to be clumped.

We claim: 
     
       1. A method of adhesion which comprises (a) applying onto a substrate having a curved surface a liquid two-step reactive type tacky adhesive agent comprising (1) a non-solvent or high-solid isocyanate compound, (2) a curing agent therefor and (3) a component consisting of a vinyl compound having one photopolymerizable vinyl group per molecule and a vinyl compound having at least two photopolymerizable vinyl groups per molecule, the weight of the former vinyl compound being in the range of 30 to 100 weight % of component (3) and the porportion of component (3) being about 5 to 80 weight % of the total amount of the tacky adhesive agent, (b) irradiating the whole applied surface with light to develop tackiness at a glass transition temperature of the applied agent after irradiating with light not exceeding about 20° C., and (c) adhering the substrate to a material to be bonded to the said curved surface through the said adhesive agent without clamping, while the tackiness is retained, followed by curing at room temperature. 
     
     
       2. A method of adhesion as claimed in claim 1, wherein the component (1) is an isocyanate compound and the component (2) is an acrylic polyol. 
     
     
       3. A method of adhesion as claimed in claim 1, wherein the component (3) is one selected from the group consisting of poly(meth)acrylates, epoxy poly(meth)acrylates, polyester poly(meth)acrylates and polyurethane poly(meth) acrylates. 
     
     
       4. A method of adhesion as claimed in claim 1, wherein the amount of the application rate is one providing a coating film of a thickness of about 10 to 300 μ. 
     
     
       5. A method of adhesion as claimed in claim 1, wherein the light is ultraviolet light generated by a high-voltage mercury lamp.